(A) Field of the Invention
The present invention relates to a low-noise block, and more particularly, to a low-noise block with low current.
(B) Description of the Related Art
When transmitting in a cable, the higher the frequency a signal has, the more severe it degrades. To prevent satellite signals, which are high frequency signals, from degrading, ordinarily there should be a low-noise block at the receiver of a satellite system. The low-noise block down-converts satellite signals into intermediate-frequency signals to maintain the quality of the transmission signal for the following process.
FIG. 1 shows a block diagram of a conventional low-noise block. The low-noise block 101 comprises a low-noise amplifier 102, a local oscillator 103, a mixer 104, an IF-amplifier 105, a regulator 106, a radio-frequency (RF) choke L1, and capacitances C1 to C3. The low-noise amplifier 102 amplifies a received high-band signal. The local oscillator 103 generates a local-frequency signal. The mixer 104 mixes the local-frequency signal and the received high-band signal into an intermediate-frequency signal. The IF-amplifier 105 amplifies the intermediate-frequency signal. The regulator 106 is coupled to the low-noise amplifier 102, the local oscillator 103 and the IF-amplifier 105 to provide a regular voltage to the low-noise amplifier 102, the local oscillator 103, the mixer 104 and the IF-amplifier 105. The capacitances C1 to C3 filter out the AC component from the passing current. The capacitance C1 is coupled to the voltage input of the low-noise amplifier 102 and ground. The capacitance C2 is coupled to the voltage input of the local oscillator 103 and ground. The capacitance C3 is coupled to the voltage input of the IF-amplifier 105 and ground.
As shown in FIG. 1, the regulator 106 simultaneously provides current to the low-noise amplifier 102, the local oscillator 103, the mixer 104 and the IF-amplifier 105. The total current of the three paths is significant. Therefore, there is a need to design a low-noise block with low current.